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Are We Close to Solving the Mystery of IBS?

Written by Alexia Severson
| Published on January 14, 2014

MRI technology opens the new door to a new understanding of irritable bowel syndrome and dietary changes that may help IBS sufferers.

Doctors today have to rely on X-ray scans and patients’ descriptions of their symptoms to diagnose irritable bowel syndrome (IBS). But scientists at the University of Nottingham’s Digestive Diseases Centre in the U.K. have discovered a new way of investigating the illness using MRIs, which could affect how doctors diagnose and treat IBS in the future.

IBS is a functional gastrointestinal disorder caused by changes in how the GI tract works. The most common symptoms are diarrhea, constipation, gas, bloating, and chronic abdominal pain. IBS can be diagnosed if a patient experiences one or more of these symptoms at least three times a month for a period of three months or longer, according to the National Digestive Diseases Information Clearinghouse.

However, because the causes and symptoms of IBS vary from person to person, it can be difficult for doctors to treat.

A New Method to Diagnose IBS

The Nottingham researchers conducted three separate studies of the gut. In the first, published online in Neurogastroenterology and Motility, scientists were able to image the colon and divide it into three functional regions.

The ascending colon is a storage and fermentation area, where unabsorbed food residue is broken down by bacteria. The transverse colon is a storage area for the residue left over after bacterial processing, while the descending colon pushes waste down and out of the body.

Using MRI scans, the scientists were able to measure the volumes of these three regions of the colon in patients with IBS in a way that’s never been done before, allowing them to compare the motion of their colons with that of a normal, healthy gut.

They found that in IBS patients the ascending colon does not relax as much to make room for a meal as that part of the colon does in healthy people.

In the second study, also published in Neurogastroenterology and Motility, researchers had volunteers ingest specially designed markers that are visible on MRI scans to measure the time it takes for food to travel through the bowel. Scientists were able to image the gut over a 24-hour period to see how far the MRI markers had moved.

According to researchers, this method can help doctors assess whether a patient has normal or delayed gut movements. It is also an ideal method for children or young women who may be pregnant and should avoid being exposed to radiation from X-rays.

Fructose, Gluten, and the FODMAP Diet

Researchers also used this colonic imaging technique to see how fructose, a type of sugar found in fruit, affected the gut of healthy volunteers in a third study published online in the American Journal of Gastroenterology. They are now repeating this study in patients with IBS.

Previous research has shown that diets that limit fructose, such as the FODMAP system, can improve IBS symptoms, and these MRI studies reveal why that improvement might occur.

Fructose is difficult to absorb and can ferment in the gut, causing the small intestine and colon to become bloated with gas. Researchers hope to find out whether this bloating corresponds with symptoms in IBS sufferers.

Unlocking the Mystery of IBS

MRI scans may provide an objective way for doctors to measure IBS, said Stephen Wangen, ND, co-founder and Medical Director of the IBS Treatment Center in Seattle, but it does not pinpoint the cause of IBS.

“In this latest research, they found that the MRI can measure changes in the colon that are associated with when patients experience IBS,” Wangen said in an interview with Healthline. “These changes are interesting, but keep in mind that those changes are symptoms of IBS. The changes in the colon occur because of the IBS, not the other way around. They should not be confused with information that explains what is causing IBS.”

But progress is being made in other areas, Wangen said.

“The medical community is slowly beginning to realize the huge significance of the role that the ecosystem of the digestive tract plays in health,” he said.

By looking at the number and types of bacteria that live in each patient's gut, doctors in the future may be able to manipulate these gut microbiomes to help the GI tract function more smoothly.

“The future of IBS is about acknowledging the uniqueness of each patient, and the vital impact that diet has, both on this ecosystem and on inflammation,” Wangen said. “It's not just about individual nutrients, it's about the whole food and how your body responds to it. Understanding these issues is the key to curing IBS.”

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